There are 8.22 million single-unit trucks registered in the United States, which travel more than 110.7 billion miles each year. Although single-unit trucks comprise three percent of registered motor vehicles and four percent of miles traveled, they are involved in nine percent of fatalities among passenger vehicle occupants in multivehicle crashes. Crashes involving single-unit trucks and passenger vehicles pose a hazard to passenger vehicle occupants due to the differences in weight, bumper height, and vehicle stiffness.
The NTSB undertook this study because of concerns about the safety record of single-unit trucks and an interest in identifying countermeasures to address the risks posed by these vehicles. One of the concerns is that single-unit trucks are excluded from some safety rules applicable to tractor-trailers. This study used a variety of data sources, including state records of police and hospital reports, federal databases, and case reviews of selected single-unit truck crashes. Risks were compared between single-unit trucks and tractor-trailers.
The study found that the adverse effects of single-unit truck crashes have been underestimated in the past because these trucks are frequently misclassified and thus undercounted in federal and state databases (approximately 20 percent in the case of fatalities). There are substantial societal impacts resulting from single-unit truck crashes, including deaths, non-fatal injuries, hospitalizations, and hospital costs.
Areas identified for safety improvements include the need to (1) enhance the ability of drivers of single-unit trucks to detect vulnerable road users such as pedestrians and cyclists, (2) prevent passenger vehicles from underriding the rears and sides of single-unit trucks, (3) improve conspicuity of single-unit trucks, (4) improve federal and state databases on large truck crashes, (5) continue the functions of databases vital for accurate fatality data or that link hospital data with police reports, (6) examine the frequency and consequences of single-unit truck drivers operating with an invalid license, and (7) research the potential benefits of expanding the commercial driver’s licensure requirement to lower weight classes.